Food intolerance

What is food intolerance?

Food intolerance is a type of food sensitivity that refers to all non-immunological reactions to food. Food intolerance reactions are different to food allergies as they are caused by food additives and naturally occurring food chemicals as opposed to specific food proteins as is the case for allergies (see food allergies for more information). Some food intolerances are caused by defects in the body’s ability to digest food. Such examples include lactose (sugar in milk) intolerance and fructose (sugar in certain fruits and vegetables) intolerance.

How common are food intolerance reactions?

Food intolerance reactions are more common than allergies and are estimated to affect up to 20% of the population (children and adults). Any age group can be affected and the sensitivity tends to be lifelong.

What are the symptoms?

Food intolerance can result in a range of symptoms that can affect the following bodily systems:

• Gastrointestinal tract: bloating, diarrhoea, constipation, stomach pain
• Respiratory tract: itchy runny nose, sinus congestion
• Nervous system: irritable behaviour, overactivity, headaches, migraines, fatigue
• Skin: nappy rash, eczema, hives, swellings, mouth ulcers

Food intolerance is hereditary and usually involves the same bodily system across generations.

What types of foods cause reactions?

People with food intolerance can commonly react to several chemicals, all of which can be found in a wide range of foods. Such chemicals include:

• Salicylates (found in certain fruits and vegetables)
• Amines (found in fermented products and certain fruits and vegetables)
• Glutamates (such as MSG and naturally occurring glutamates in certain fruits and vegetables)
• Preservatives such as nitrates (in processed meats), propionates (in bread) and benzoates (in flavoured drinks) and sulphites (in dried fruit)
• Artificial colours

Reactions occur depending on the dose of chemical consumed and tend to be delayed (hours to days) which makes it difficult to identify the cause.

How is it diagnosed?

Unlike food allergies, there are currently no reliable clinical tests to diagnose food intolerance. It is recommended that people with suspected food intolerance seek professional advice from an Accredited Practising Dietitian (APD) who will advise on the best dietary approach needed to identify the problem foods. The APD will also ensure that the individual has adequate nutrition both during the investigation and after diagnosis.                                                           

Source: ASCIA Infant Feeding Advice 2010